__init__.py

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# -*- coding: utf-8; -*-
#
# Copyright (c) 2016 Álan Crístoffer
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.

import importlib.machinery
import os
import sys

# path to the drivers folder
__modules_path = os.path.dirname(os.path.realpath(__file__))
# tries to load every file in the drivers folder
__modules = (__load_driver(driver) for driver in os.listdir(__modules_path))
# filters out the False elements, leaving only valid drivers
__modules = (d for d in __modules if d)
# only installed drivers that are available in this platform
__available = None



def available_drivers():
    global __modules
    global __available

    if type(__modules) is not list:
        __modules = list(__modules)

    if not __available:
        __available = [d.ahioDriverInfo.NAME
                       for d in __modules
                       if d.ahioDriverInfo.AVAILABLE]

    return __available



def driver_info(name):
    driver = __locate_driver_named(name)
    return driver.ahioDriverInfo if driver else None



def new_driver_object(name):
    driver = __locate_driver_named(name)
    return driver.Driver() if driver else None



def __load_driver(name):
    try:
        mod_name = 'ahio.drivers.' + name.replace('.py', '')
        driver_path = __modules_path + '/' + name
        loader = importlib.machinery.SourceFileLoader(mod_name, driver_path)
        driver = loader.load_module()
        return driver if hasattr(driver, 'ahioDriverInfo') else False
    except Exception:
        return False



def __locate_driver_named(name):
    global __modules

    if type(__modules) is not list:
        __modules = list(__modules)

    ms = [d for d in __modules if d.ahioDriverInfo.NAME == name]
    if not ms:
        return None
    return ms[0]